Inhibition of 37/67kDa Laminin-1 Receptor Restores APP Maturation and Reduces Amyloid-β in Human Skin Fibroblasts from Familial Alzheimer’s Disease

Abstract

Alzheimer’s disease (AD) is a fatal neurodegenerative disorder caused by protein misfolding and aggregation, affecting brain function and causing dementia. Amyloid beta (Aβ), a peptide deriving from amyloid precursor protein (APP) cleavage by-and γ-secretases, is considered a pathological hallmark of AD. Our previous study, together with several lines of evidence, identified a strict link between APP, Aβ and 37/67kDa laminin receptor (LR), finding the possibility to regulate intracellular APP localization and maturation through modulation of the receptor. Here, we report that in fibroblasts from familial AD (fAD), APP was prevalently expressed as an immature isoform and accumulated preferentially in the transferrin-positive recycling compartment rather than in the Golgi apparatus. Moreover, besides the altered mitochondrial network exhibited by fAD patient cells, the levels of pAkt and pGSK3 were reduced in respect to healthy control fibroblasts and were accompanied by an increased amount of secreted Aβ in conditioned medium from cell cultures. Interestingly, these features were reversed by inhibition of 37/67kDa LR by NSC47924 a small molecule that was able to rescue the “typical” APP localization in the Golgi apparatus, with consequences on the Aβ level and mitochondrial network. Altogether, these findings suggest that 37/67kDa LR modulation may represent a useful tool to control APP trafficking and Aβ levels with implications in Alzheimer’s disease.

Endosomal trafficking and related genetic underpinnings as a hub in Alzheimer's disease

“…Tan & Gleeson, 2019). Accordingly, we and others have demonstrated that intracellular trafficking is extremely important for the correct protein function and processing (Bhattacharya, Izzo, et al, 2020;Sarnataro et al, 2017;J. Z.…”

“…The use of receptor inhibitors revealed the possibility to modulate APP maturation and intracellular localization in neuronal cells, as well as to restore the lost “correct” APP intracellular localization, mitochondrial network and Aβ levels in fibroblasts from familial AD‐affected patients (Bhattacharya, Izzo, et al, 2020 ; Bhattacharya, Limone, et al, 2020 ).…”

High-Fat Diet Leads to Reduced Protein O-GlcNAcylation and Mitochondrial Defects Promoting the Development of Alzheimer’s Disease Signatures

“…Furthermore, the well-known involvement of O-GlcNAcylation in controlling protein localization, function, and interaction has acquired special interest with regards to APP. Indeed, this posttranslational modification (PTM) has been demonstrated to control APP maturation and trafficking, thus affecting the generation Aβ [ 32 , 33 , 34 ]. Moreover, mitochondrial dysfunction and the associated oxidative stress have been recognized as important biological mechanisms contributing to insulin resistance and diabetic complications [ 35 , 36 , 37 , 38 ].…”

The Crosstalk between N-Formyl Peptide Receptors and uPAR in Systemic Sclerosis: Molecular Mechanisms, Pathogenetic Role and Therapeutic Opportunities

“…Primary skin fibroblasts isolated from punch biopsies of SSc and healthy skin were mechanically dissociated under a light microscope and trypsinizated, as previously described [ 31 , 48 ]. Cells were plated and cultured in monolayer in DMEM (Life Technologies) supplemented with 10% heat inactivated FBS (Life Technologies), 100 U/mL penicillin G sodium and 100 mg/mL streptomycin sulfate, at 37 °C, in a humidified atmosphere of 5% CO 2 .…”